Default beam identification and beam failure detection in cross carrier scheduling

ABSTRACT

Methods, systems, and devices for wireless communications are described. A base station may transmit a first downlink grant (e.g., a PDCCH transmission) for a first data transmission (e.g., a PDSCH transmission) over a first component carrier; the first data transmission over a second component carrier; and a second downlink grant (e.g., another PDCCH transmission) for a second data transmission (e.g., another PDSCH transmission) over the second component carrier. A user equipment (UE) receives the first data transmission over a first beam and may use the first beam for receiving the second data transmission. Additionally or alternatively, the UE may receive a configuration message indicating a set of TCI states for downlink data transmissions to the UE; identify one or more reference signals monitor for beam failure detection (BFD), identify one or more BFD beams, monitor the identified one or more reference signals; and selectively trigger a beam failure reporting procedure.

CROSS REFERENCE

The present application for patent is a Divisional of U.S. patentapplication Ser. No. 16/738,912 by JOHN WILSON et al., entitled “DEFAULTBEAM IDENTIFICATION AND BEAM FAILURE DETECTION IN CROSS CARRIERSCHEDULING” filed Jan. 9, 2020, which claims the benefit of U.S.Provisional Patent Application No. 62/791,506 by JOHN WILSON et al.,entitled “DEFAULT BEAM IDENTIFICATION AND BEAM FAILURE DETECTION INCROSS CARRIER SCHEDULING,” filed Jan. 11, 2019, assigned to the assigneehereof, and expressly incorporated herein.

BACKGROUND

The following relates generally to wireless communications and todefault beam identification and beam failure detection for cross carrierscheduling.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude a number of base stations or network access nodes, eachsimultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

SUMMARY

The described techniques relate to improved methods, systems, devices,and apparatuses that support default beam identification and beamfailure detection for cross carrier scheduling. Generally, the describedtechniques provide for a UE to reuse a default beam from a firstcross-carrier scheduled data transmission (such as a physical downlinkshared channel (PDSCH) transmission) when receiving a secondcross-carrier scheduled data transmission (e.g., another PDSCHtransmission) that occurs within a threshold amount of time afterreceiving a downlink grant (such as in a physical downlink controlchannel (PDCCH) transmission) for the second cross-carrier scheduleddata transmission

Additionally or alternatively, a UE may perform beam failure detection(BFD) to determine if beam failure has occurred. As the componentcarrier upon which a cross-carrier scheduled PDSCH transmission occursmay not be associated with a control resource set (CORESET), the UE mayrely on a quantity of down selected transmission configuration indicator(TCI) states configured for the UE to determine which reference signalsand, by extension, which beams to monitor for beam failure. If the UEdetects a beam failure from the monitored beams, the UE may trigger abeam failure reporting procedure (e.g., beam recovery).

In some cases, a UE in a wireless communications system may be capableof communicating over multiple component carriers or wireless channels.Such UEs may implement cross-carrier scheduling by receiving controlinformation on one component carrier that schedules downlinktransmissions on another component carrier. Improved techniques fordefault beam identification and BFD for cross-carrier scheduling aredesired.

A method of wireless communication at a UE is described. The method mayinclude receiving, over a first component carrier, a first downlinkgrant for a first data transmission over a second component carrier,receiving the first data transmission over the second component carrierusing a first beam as a default beam, receiving, over the firstcomponent carrier, a second downlink grant for a second datatransmission over the second component carrier, selecting the first beamas the default beam for the second data transmission based on a receivetime of the second data transmission occurring within a first thresholdtime window following the second downlink grant, and receiving, based onthe second downlink grant, the second data transmission over the secondcomponent carrier using the first beam as the default beam.

An apparatus for wireless communication at a UE is described. Theapparatus may include a processor, memory coupled to the processor, andinstructions stored in the memory. The instructions may be executable bythe processor to cause the apparatus to receive, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier, receive the first data transmission over thesecond component carrier using a first beam as a default beam, receive,over the first component carrier, a second downlink grant for a seconddata transmission over the second component carrier, select the firstbeam as the default beam for the second data transmission based on areceive time of the second data transmission occurring within a firstthreshold time window following the second downlink grant, and receive,based on the second downlink grant, the second data transmission overthe second component carrier using the first beam as the default beam.

Another apparatus for wireless communication at a UE is described. Theapparatus may include means for receiving, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier, receiving the first data transmission over thesecond component carrier using a first beam as a default beam,receiving, over the first component carrier, a second downlink grant fora second data transmission over the second component carrier, selectingthe first beam as the default beam for the second data transmissionbased on a receive time of the second data transmission occurring withina first threshold time window following the second downlink grant, andreceiving, based on the second downlink grant, the second datatransmission over the second component carrier using the first beam asthe default beam.

A non-transitory computer-readable medium storing code for wirelesscommunication at a UE is described. The code may include instructionsexecutable by a processor to receive, over a first component carrier, afirst downlink grant for a first data transmission over a secondcomponent carrier, receive the first data transmission over the secondcomponent carrier using a first beam as a default beam, receive, overthe first component carrier, a second downlink grant for a second datatransmission over the second component carrier, select the first beam asthe default beam for the second data transmission based on a receivetime of the second data transmission occurring within a first thresholdtime window following the second downlink grant, and receive, based onthe second downlink grant, the second data transmission over the secondcomponent carrier using the first beam as the default beam.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving an indicationof the first beam as the default beam for the first data transmission.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the indication of the firstbeam may be received in connection with the first downlink grant.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a receive time of the firstdata transmission occurs outside of the first threshold time windowfollowing the first downlink grant.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the indication of the firstbeam may be received in connection with a radio resource control (RRC)message.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining that areceive time of the second downlink grant occurs after a secondthreshold time window following a receive time of the first datatransmission, where selecting the first beam as the default beam may befurther based on the determination.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting feedbackinformation for the first data transmission, where the second thresholdtime window may be defined based on a transmit time of the feedbackinformation.

A method of wireless communication at a UE is described. The method mayinclude receiving a configuration message indicating a set of TCI statesfor downlink data transmissions to the UE, identifying one or morereference signals to monitor for beam failure detection based on theindicated set of TCI states, identifying one or more beam failuredetection beams based on the indicated set of TCI states and theidentified one or more reference signals, monitoring the identified oneor more reference signals using the identified one or more beam failuredetection beams, and selectively triggering a beam failure reportingprocedure based on the monitoring.

An apparatus for wireless communication at a UE is described. Theapparatus may include a processor, memory coupled to the processor, andinstructions stored in the memory. The instructions may be executable bythe processor to cause the apparatus to receive a configuration messageindicating a set of TCI states for downlink data transmissions to theUE, identify one or more reference signals to monitor for beam failuredetection based on the indicated set of TCI states, identify one or morebeam failure detection beams based on the indicated set of TCI statesand the identified one or more reference signals, monitor the identifiedone or more reference signals using the identified one or more beamfailure detection beams, and selectively trigger a beam failurereporting procedure based on the monitoring.

Another apparatus for wireless communication at a UE is described. Theapparatus may include means for receiving a configuration messageindicating a set of TCI states for downlink data transmissions to theUE, identifying one or more reference signals to monitor for beamfailure detection based on the indicated set of TCI states, identifyingone or more beam failure detection beams based on the indicated set ofTCI states and the identified one or more reference signals, monitoringthe identified one or more reference signals using the identified one ormore beam failure detection beams, and selectively triggering a beamfailure reporting procedure based on the monitoring.

A non-transitory computer-readable medium storing code for wirelesscommunication at a UE is described. The code may include instructionsexecutable by a processor to receive a configuration message indicatinga set of TCI states for downlink data transmissions to the UE, identifyone or more reference signals to monitor for beam failure detectionbased on the indicated set of TCI states, identify one or more beamfailure detection beams based on the indicated set of TCI states and theidentified one or more reference signals, monitor the identified one ormore reference signals using the identified one or more beam failuredetection beams, and selectively trigger a beam failure reportingprocedure based on the monitoring.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, identifying the one or morereference signals to monitor for beam failure detection may includeoperations, features, means, or instructions for identifying a referencesignal type associated with each TCI state in the set of TCI states, andselecting, from the set of TCI states, a subset of TCI states for beamfailure detection based on the reference signal type associated witheach TCI state in the set of TCI states.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, determining the referencesignal type associated with each TCI state in the set of TCI states mayinclude operations, features, means, or instructions for determiningthat a TCI state in the set of TCI states may be associated withmultiple reference signal types, and selecting, based on an entryassociated with the TCI state, one of the reference signal typesassociated with the TCI state for use in selecting the subset of TCIstates.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the entry associated with theTCI state may be a Type D entry of the TCI state.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, selecting the subset of TCIstates for beam failure detection may include operations, features,means, or instructions for determining an ascending or descending orderof TCI states in the set of TCI states, and identifying a fixed numberof TCI states for the subset of TCI states based on the ascending ordescending order.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying the one ormore reference signals may be further based on an amount of repetitionfor a given reference signal type during the downlink datatransmissions.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying the one ormore reference signals may be further based on a periodicity of a givenreference signal type during the downlink data transmissions.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying the one ormore reference signals may be further based on a receive powerassociated with a given reference signal type.

A method of wireless communication at a base station is described. Themethod may include transmitting, over a first component carrier, a firstdownlink grant for a first data transmission over a second componentcarrier, transmitting the first data transmission over the secondcomponent carrier using a first beam as a default beam, transmitting,over the first component carrier, a second downlink grant for a seconddata transmission over the second component carrier, selecting the firstbeam as the default beam for the second data transmission based on areceive time of the second data transmission occurring within a firstthreshold time window following the second downlink grant, andtransmitting, based on the second downlink grant, the second datatransmission over the second component carrier using the first beam asthe default beam.

An apparatus for wireless communication at a base station is described.The apparatus may include a processor, memory coupled to the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to transmit, over afirst component carrier, a first downlink grant for a first datatransmission over a second component carrier, transmit the first datatransmission over the second component carrier using a first beam as adefault beam, transmit, over the first component carrier, a seconddownlink grant for a second data transmission over the second componentcarrier, select the first beam as the default beam for the second datatransmission based on a receive time of the second data transmissionoccurring within a first threshold time window following the seconddownlink grant, and transmit, based on the second downlink grant, thesecond data transmission over the second component carrier using thefirst beam as the default beam.

Another apparatus for wireless communication at a base station isdescribed. The apparatus may include means for transmitting, over afirst component carrier, a first downlink grant for a first datatransmission over a second component carrier, transmitting the firstdata transmission over the second component carrier using a first beamas a default beam, transmitting, over the first component carrier, asecond downlink grant for a second data transmission over the secondcomponent carrier, selecting the first beam as the default beam for thesecond data transmission based on a receive time of the second datatransmission occurring within a first threshold time window followingthe second downlink grant, and transmitting, based on the seconddownlink grant, the second data transmission over the second componentcarrier using the first beam as the default beam.

A non-transitory computer-readable medium storing code for wirelesscommunication at a base station is described. The code may includeinstructions executable by a processor to transmit, over a firstcomponent carrier, a first downlink grant for a first data transmissionover a second component carrier, transmit the first data transmissionover the second component carrier using a first beam as a default beam,transmit, over the first component carrier, a second downlink grant fora second data transmission over the second component carrier, select thefirst beam as the default beam for the second data transmission based ona receive time of the second data transmission occurring within a firstthreshold time window following the second downlink grant, and transmit,based on the second downlink grant, the second data transmission overthe second component carrier using the first beam as the default beam.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting anindication of the first beam as the default beam for the first datatransmission.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the indication of the firstbeam may be transmitted in connection with the first downlink grant.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a receive time of the firstdata transmission occurs outside of the first threshold time windowfollowing the first downlink grant.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the indication of the firstbeam may be transmitted in connection with a RRC message.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining that areceive time of the second downlink grant occurs after a secondthreshold time window following a receive time of the first datatransmission, where selecting the first beam as the default beam may befurther based on the determination.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving feedbackinformation for the first data transmission, where the second thresholdtime window may be defined based on a transmit time of the feedbackinformation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure.

FIG. 2 illustrates an example of a wireless communications system thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure.

FIG. 3 illustrates an example of a cross-carrier configuration thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure.

FIG. 4 illustrates an example of a cross-carrier configuration thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure.

FIG. 5 illustrates an example of a process flow that supports defaultbeam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of a process flow that supports defaultbeam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure.

FIGS. 7 and 8 show block diagrams of devices that support default beamidentification and beam failure detection for cross carrier schedulingin accordance with aspects of the present disclosure.

FIG. 9 shows a block diagram of a communications manager that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure.

FIG. 10 shows a diagram of a system including a device that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure.

FIGS. 11 and 12 show block diagrams of devices that support default beamidentification and beam failure detection for cross carrier schedulingin accordance with aspects of the present disclosure.

FIG. 13 shows a block diagram of a communications manager that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure.

FIG. 14 shows a diagram of a system including a device that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure.

FIGS. 15 through 20 show flowcharts illustrating methods that supportdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

In some cases, a UE may perform communications with a base station usinga default beam. The UE may determine the default beam from a previouslyreceived (e.g., the last received) PDCCH and may use a default beam toreceive a PDSCH transmission from the base station. In cases where atime k₀ between receiving a PDCCH transmission and receiving a PDSCHtransmission is less than a threshold, the UE may assume that thedefault beam is a lowest CORESET ID of a previous slot (e.g., the latestslot).

The UE may, additionally or alternatively, perform BFD with the basestation. For instance, the UE may perform BFD based on a BFD set whichmay contain RRC-configured reference signals or reference signals linkedto CORESETs being monitored. Reference signals configured by RRC may besemi-statically configured, while reference signals linked to CORESETsmay be dynamically configured. The UE may monitor the reference signalsand may determine beam failure has occurred if a block error rate (BLER)associated with each reference signal is larger than an out-of-sync(OOS) BLER. As such, default beam determination (e.g., for when a PDSCHtransmission is received before a corresponding PDCCH transmission isprocessed) and/or dynamic BFD updating may rely on CORESETs.

In some cases (e.g., cross-carrier scheduling), however, a CORESET maynot be available to a UE. Cross-carrier scheduling may, for instance,involve a UE receiving a PDCCH transmission with a first componentcarrier and receiving a PDSCH transmission with a second componentcarrier. The second component carrier, however, may not be associatedwith a CORESET. As such, when a PDSCH transmission is received before aPDCCH transmission is decoded, the UE may not be able to rely on thelowest CORESET ID of a previous slot in the component carrier (e.g., thelatest slot). Additionally or alternatively, the UE may not be able tolink the reference signals of the BFD set to a CORESET to be monitored,as the PDSCH of the second component carrier may not be associated witha CORESET. As such, dynamic updating of the BFD, such as through linkingreference signals to CORESETs, may not be readily achievable throughcurrent methods.

In order to determine a default beam when a CORESET is unavailable(e.g., during cross-carrier scheduling), a UE may decode a downlinkgrant, such as a PDCCH transmission, and determine a default beam basedon a previous cross-carrier scheduled data transmission beam, such as aPDSCH beam. For instance, the UE may determine a beam used previously totransmit the data transmission (e.g., a PDSCH transmission) in thesecond component carrier and may use the beam to receive a next datatransmission if the next data transmission is received within athreshold time window after receiving a next downlink grant (e.g., ifthe next data transmission is received before the next downlink granthas been processed). Additionally or alternatively, the UE may receivean indication of the initial default beam from a base station (e.g., RRCsignaling) that may indicate which default beam the UE is to use forreceiving a next data transmission. Additionally or alternatively, theUE may wait to use to use the previous cross-carrier scheduled datatransmission beam until a second threshold time window has elapsed. Forinstance, the UE may wait until the UE has transmitted feedbackinformation (e.g., an acknowledgement (ACK) or non-acknowledgement(NACK)) in response to receiving the PDSCH transmission.

In order to perform BFD when a CORESET is not available (e.g., duringcross-carrier scheduling), a UE may rely on a configuration message(e.g., a medium access control (MAC) control element (MAC-CE))indicating a set of downselected TCI states. The UE may use the TCIstates to update a BFD set, where the BFD set may be comprised of aquantity of reference signals from the downselected TCI states. Tochoose which reference signals are to be used in the BFD set, the UE mayapply one or more rules. For instance, the reference signals may bechosen based on which reference signals have the lowest periodicity,which reference signals have the largest reference signal received power(RSRP), the order of the downselected TCI states, the quasi-co location(QCL) type of a reference signal, or a combination. In some cases,repeats of reference signals among the downselected TCI states may beremoved from consideration. After updating the BFD set, the UE maymonitor BFD beams associated with each reference signal of the BFD setand may selectively trigger a beam failure reporting procedure (e.g.,beam recovery) if the UE determines beam failure has occurred.

Aspects of the disclosure are initially described in the context of awireless communications system. Aspects of the disclosure areadditionally described in the context of an additional wirelesscommunications system, cross-carrier configurations, and process flows.Aspects of the disclosure are further illustrated by and described withreference to apparatus diagrams, system diagrams, and flowcharts thatrelate to default beam identification and beam failure detection forcross carrier scheduling.

FIG. 1 illustrates an example of a wireless communications system 100that supports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. The wireless communications system 100 includes basestations 105, UEs 115, and a core network 130. In some examples, thewireless communications system 100 may be a Long Term Evolution (LTE)network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a NewRadio (NR) network. In some cases, wireless communications system 100may support enhanced broadband communications, ultra-reliable (e.g.,mission critical) communications, low latency communications, orcommunications with low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB orgiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples half-duplexcommunications may be performed at a reduced peak rate. Other powerconservation techniques for UEs 115 include entering a power saving“deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPMultimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, since thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (e.g., less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that may be capable of toleratinginterference from other users.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In somecases, operations in unlicensed bands may be based on a carrieraggregation configuration in conjunction with component carriersoperating in a licensed band (e.g., LAA). Operations in unlicensedspectrum may include downlink transmissions, uplink transmissions,peer-to-peer transmissions, or a combination of these. Duplexing inunlicensed spectrum may be based on frequency division duplexing (FDD),time division duplexing (TDD), or a combination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving device is equipped with one or moreantennas. MIMO communications may employ multipath signal propagation toincrease the spectral efficiency by transmitting or receiving multiplesignals via different spatial layers, which may be referred to asspatial multiplexing. The multiple signals may, for example, betransmitted by the transmitting device via different antennas ordifferent combinations of antennas. Likewise, the multiple signals maybe received by the receiving device via different antennas or differentcombinations of antennas. Each of the multiple signals may be referredto as a separate spatial stream, and may carry bits associated with thesame data stream (e.g., the same codeword) or different data streams.Different spatial layers may be associated with different antenna portsused for channel measurement and reporting. MIMO techniques includesingle-user MIMO (SU-MIMO) where multiple spatial layers are transmittedto the same receiving device, and multiple-user MIMO (MU-MIMO) wheremultiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g., synchronizationsignals, reference signals, beam selection signals, or other controlsignals) may be transmitted by a base station 105 multiple times indifferent directions, which may include a signal being transmittedaccording to different beamforming weight sets associated with differentdirections of transmission. Transmissions in different beam directionsmay be used to identify (e.g., by the base station 105 or a receivingdevice, such as a UE 115) a beam direction for subsequent transmissionand/or reception by the base station 105.

Some signals, such as data signals associated with a particularreceiving device, may be transmitted by a base station 105 in a singlebeam direction (e.g., a direction associated with the receiving device,such as a UE 115). In some examples, the beam direction associated withtransmissions along a single beam direction may be determined based atleast in in part on a signal that was transmitted in different beamdirections. For example, a UE 115 may receive one or more of the signalstransmitted by the base station 105 in different directions, and the UE115 may report to the base station 105 an indication of the signal itreceived with a highest signal quality, or an otherwise acceptablesignal quality. Although these techniques are described with referenceto signals transmitted in one or more directions by a base station 105,a UE 115 may employ similar techniques for transmitting signals multipletimes in different directions (e.g., for identifying a beam directionfor subsequent transmission or reception by the UE 115), or transmittinga signal in a single direction (e.g., for transmitting data to areceiving device).

A receiving device (e.g., a UE 115, which may be an example of a mmWreceiving device) may try multiple receive beams when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets applied to signals receivedat a plurality of antenna elements of an antenna array, or by processingreceived signals according to different receive beamforming weight setsapplied to signals received at a plurality of antenna elements of anantenna array, any of which may be referred to as “listening” accordingto different receive beams or receive directions. In some examples areceiving device may use a single receive beam to receive along a singlebeam direction (e.g., when receiving a data signal). The single receivebeam may be aligned in a beam direction determined based at least inpart on listening according to different receive beam directions (e.g.,a beam direction determined to have a highest signal strength, highestsignal-to-noise ratio, or otherwise acceptable signal quality based atleast in part on listening according to multiple beam directions).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer mayperform packet segmentation and reassembly to communicate over logicalchannels. A MAC layer may perform priority handling and multiplexing oflogical channels into transport channels. The MAC layer may also usehybrid automatic repeat request (HARM) to provide retransmission at theMAC layer to improve link efficiency. In the control plane, the RRCprotocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and a base station 105 or corenetwork 130 supporting radio bearers for user plane data. At thePhysical layer, transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period of T_(s)=1/30,720,000 seconds. Time intervals of a communications resource may beorganized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. In someexamples, a threshold time window may be determined based at least inpart on the subcarrier spacing. Further, some wireless communicationssystems may implement slot aggregation in which multiple slots ormini-slots are aggregated together and used for communication between aUE 115 and a base station 105.

The term “carrier” or “component carrier” refers to a set of radiofrequency spectrum resources having a defined physical layer structurefor supporting communications over a communication link 125. Forexample, a carrier of a communication link 125 may include a portion ofa radio frequency spectrum band that is operated according to physicallayer channels for a given radio access technology. Each physical layerchannel may carry user data, control information, or other signaling. Acarrier may be associated with a pre-defined frequency channel (e.g., anevolved universal mobile telecommunication system terrestrial radioaccess (E-UTRA) absolute radio frequency channel number (EARFCN)), andmay be positioned according to a channel raster for discovery by UEs115. Carriers may be downlink or uplink (e.g., in an FDD mode), or beconfigured to carry downlink and uplink communications (e.g., in a TDDmode). In some examples, signal waveforms transmitted over a carrier maybe made up of multiple sub-carriers (e.g., using multi-carriermodulation (MCM) techniques such as orthogonal frequency divisionmultiplexing (OFDM) or discrete Fourier transform spread OFDM(DFT-S-OFDM)).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR).For example, communications over a carrier may be organized according toTTIs or slots, each of which may include user data as well as controlinformation or signaling to support decoding the user data. A carriermay also include dedicated acquisition signaling (e.g., synchronizationsignals or system information, etc.) and control signaling thatcoordinates operation for the carrier. In some examples (e.g., in acarrier aggregation configuration), a carrier may also have acquisitionsignaling or control signaling that coordinates operations for othercarriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation or multi-carrier operation. A UE 115 may beconfigured with multiple downlink component carriers and one or moreuplink component carriers according to a carrier aggregationconfiguration. Carrier aggregation may be used with both FDD and TDDcomponent carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including wider carrier or frequency channel bandwidth, shortersymbol duration, shorter TTI duration, or modified control channelconfiguration. In some cases, an eCC may be associated with a carrieraggregation configuration or a dual connectivity configuration (e.g.,when multiple serving cells have a suboptimal or non-ideal backhaullink). An eCC may also be configured for use in unlicensed spectrum orshared spectrum (e.g., where more than one operator is allowed to usethe spectrum). An eCC characterized by wide carrier bandwidth mayinclude one or more segments that may be utilized by UEs 115 that arenot capable of monitoring the whole carrier bandwidth or are otherwiseconfigured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than othercomponent carriers, which may include use of a reduced symbol durationas compared with symbol durations of the other component carriers. Ashorter symbol duration may be associated with increased spacing betweenadjacent subcarriers. A device, such as a UE 115 or base station 105,utilizing eCCs may transmit wideband signals (e.g., according tofrequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc.) atreduced symbol durations (e.g., 16.67 microseconds). A TTI in eCC mayconsist of one or multiple symbol periods. In some cases, the TTIduration (that is, the number of symbol periods in a TTI) may bevariable.

Wireless communications system 100 may be an NR system that may utilizeany combination of licensed, shared, and unlicensed spectrum bands,among others. The flexibility of eCC symbol duration and subcarrierspacing may allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossthe frequency domain) and horizontal (e.g., across the time domain)sharing of resources.

In some cases, a UE 115 may include a UE communication manager 150 thatmay receive a PDCCH transmission and decode the PDCCH transmission todetermine a default beam over which to receive a corresponding PDSCHtransmission. This determination may involve identifying a TCI state ofthe PDCCH transmission. However, in some cases, the UE 115 may receivethe PDSCH transmission before the UE 115 is able to decode the PDCCHtransmission. In such cases, the UE communication manager 150 may assumethat that the default beam is a lowest CORESET ID of a previous slot(e.g., the latest slot).

Additionally or alternatively, the UE communication manager 150 mayperform BFD. Beam failure may occur whenever channel conditions are poorand the UE 115 is incapable of or impeded from receiving informationfrom a transmitter (e.g., a transmitter of a base station 105). The UEcommunication manager 150 may monitor a set of beams contained with aBFD set which may be RRC or linked to CORESET beams (e.g., dynamicallyupdated). The UE communication manager 150 may trigger a beam failurerecovery (BFR) procedure when the beams of the BFD set fail (e.g., whenall beams of the BFD set have a BLER greater than an 00S BLER).

Either or both of determining a default beam and BFD may involve using aCORESET. However, if the UE 115 and corresponding base station areacting according to cross-carrier scheduling (e.g., between FR1 andFR2), the cross carrier scheduled component carrier may not have aCORESET. For instance, a default beam of a lowest CORESET ID of aprevious slot may be configured to operate within a component carrierassociated with a PDCCH transmission (e.g., FR1), but may not beconfigured to operate within a different component carrier (e.g., FR2).As such, the UE 115 may fail to perform default beam determination andBFD by conventional methods.

Wireless communications system 100 may support efficient techniques fordefault beam identification and beam failure detection for cross carrierscheduling. For instance, a UE 115 may receive, over a first componentcarrier and from a base station 105, a first downlink grant (e.g., aPDCCH transmission) for a first data transmission (e.g., a PDSCHtransmission) over a second component carrier. The UE 115 may receive,from the base station 105, the first data transmission over the secondcomponent carrier using a first beam as a default beam. The UE 115 mayreceive, over the first component carrier and from the base station 105,a second downlink grant for a second data transmission over the secondcomponent carrier. The UE 115, through UE communication manager 150 forexample, may select the first beam as the default beam for the seconddata transmission based on a receive time of the second datatransmission occurring within a first threshold time window followingthe second downlink grant. The UE 115 may receive, based on the seconddownlink grant and from the base station 105, the second datatransmission over the second component carrier using the first beam asthe default beam.

The methods disclosed herein may enable a UE 115 to determine a defaultbeam when a CORESET is not available, such as when the UE 115 isparticipating in cross-carrier scheduling. Further, reusing a first beamas a default beam for a second data transmission may enable a UE 115 toreceive a PDSCH without first processing a corresponding PDCCH.Receiving a default beam through RRC signaling may enable an initialPDSCH transmission to be received within a threshold time window afterreceiving the initial PDCCH transmission. Determining a default beamfrom a PDCCH, meanwhile, may enable a UE 115 to determine a default beamwithout relying on receiving additional signaling.

Additionally or alternatively, a UE 115 may receive, from a base station105, a configuration message (e.g., a MAC-CE) indicating a set of TCIstates for downlink data transmissions (e.g., a PDSCH transmission) tothe UE 115. The UE 115 may identify one or more reference signals tomonitor for BFD based on the indicated set of TCI states. The UE 115 mayidentify one or more BFD beams based on the indicated set of TCI statesand the identified one or more reference signals. The UE 115 may monitorthe identified one or more reference signals using the identified one ormore beam failure detection beams. The UE 115 may selectively trigger abeam failure reporting procedure (e.g., beam recovery) based on themonitoring.

The methods disclosed herein may enable a UE 115 to perform BFD when aCORESET is not available, such as when the UE 115 is participating incross-carrier scheduling. As such, the methods disclosed herein mayenable the UE 115 to dynamically update a set of reference signals andcorresponding BFD beams when a CORESET is not available. In some cases,choosing the reference signals from a downselected subset of TCI stateswith the lowest periodicity may enable the UE 115 to speed up BFDdetermination, as reference signals with lower periodicity may arrive atthe UE 115 more often. Additionally or alternatively, choosing thereference signals from a downselected subset of TCI states with thelargest RSRP may enable more accuracy in determining that all possiblereference signals of the downselected subset have failed (e.g., ifreference signals with the largest RSRPs fails, the reference signalswith smaller RSRPs may have also failed)

In some cases, a base station 105 may include a base stationcommunication manager 140 that may cause a transmitter of the basestation to transmit, over a first component carrier, a first downlinkgrant for a first data transmission over a second component carrier. Thebase station communication manager 140 may cause the transmitter totransmit, over a first component carrier, a first downlink grant for afirst data transmission over a second component carrier, and transmitthe first data transmission over the second component carrier using afirst beam as a default beam. The base station communication manager 140may cause the transmitter to transmit, over the first component carrier,a second downlink grant for a second data transmission over the secondcomponent carrier. The base station communication manager 140 may selectthe first beam as the default beam for the second data transmissionbased at least in part on a receive time of the second data transmissionoccurring within a first threshold time window following the seconddownlink grant. The base station communication manager 140 may cause thetransmitter to transmit, based at least in part on the second downlinkgrant, the second data transmission over the second component carrierusing the first beam as the default beam.

FIG. 2 illustrates an example of a wireless communications system 200that supports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. In some examples, wireless communications system 200 mayimplement aspects of wireless communications system 100. For instance,wireless communications system 200 may include UE 115-a and base station105-a, which may be examples of a UE 115 and a base station 105,respectively, as described with reference to FIG. 1 . Base station 105-amay serve a cell with a coverage area 110-a.

Base station 105-a may communicate with UE 115-a over component carriers205-a and 205-b. Component carrier 205-a may represent a first frequencyrange (e.g., FR1) and component carrier 205-a may represent a secondfrequency range (e.g., FR2). Component carrier 205-a may carry one ormore PDCCH transmissions 210 scheduling one or more PDSCH transmissions215 in component carrier 205-b. For instance, component carrier 205-amay carry a first PDCCH transmission 210-a which may schedule a firstPDSCH transmission 215-a within component carrier 205-b and may carry asecond PDCCH transmission 210-b which may schedule a second PDSCHtransmission 215-b.

UE 115-a, upon receiving PDCCH transmission 210-a, may decode PDCCHtransmission 210-a and use information (e.g., TCI state information)from the PDCCH transmission 210-a to determine a default beam upon whichto receive PDSCH transmission 215-a. In order to decode PDCCHtransmission 210-a and use its information to receive PDSCH transmission215-a, UE 115-a may receive PDSCH transmission 215-a after a thresholdtime 220-a (e.g., k₀), which may represent a time at which base station105-a infers that UE 115-a has processed PDCCH transmission 210-a. Inother cases, UE 115-a may receive RRC signaling (e.g., from base station105-a) that specifies the default beam. In such cases, UE 115-a mayreceive PDSCH transmission 215-a before threshold time 220-a has elapsedand may use the default beam to receive PDSCH transmission 215-a.

UE 115-a may receive second PDCCH transmission 210-b after receivingfirst PDCCH transmission 210-a. However, UE 115-a may receive PDSCHtransmission 215-b before UE 115-a is able to process PDCCH transmission210-b (e.g., before threshold time 220-b has elapsed). In such cases,base station 105-a may use the default beam indicated in PDCCHtransmission 210-a or specified via RRC signaling. After PDCCHtransmission 210-b is decoded, UE 115-a may determine a new default beamto use if a next PDSCH transmission 215 is received before a next PDCCHtransmission 210 is processed. Additionally or alternatively, UE 115-amay continue to use the default beam indicated in PDCCH transmission210-a or specified via RRC signaling.

In some cases, UE 115-a may determine the default beam (e.g., forreceiving PDSCH transmissions 215) via virtual CORESETs and/or virtualsearch spaces. Virtual CORESETs and/or virtual search spaces may giveTCI state information, but may not include a PDCCH transmission to bemonitored (e.g., the number of PDCCH transmissions to be monitored maybe 0). The TCI state of the virtual CORESETs may be updated via MAC-CEin a dynamic manner. Additionally or alternatively, in the absence ofCORESETs, virtual CORESETs may be configured to be used fordetermination of BFD sets.

In some cases, UE 115-a may perform BFD determination by using PDSCH TCIstates. For instance, UE 115-may use up to a certain number (e.g., 128)of TCI states to receive a PDSCH transmission 215, from which MAC-CE maydownselect a subset (e.g., 8). As such, UE 115-a may assume that the BFDset consists of one or more TCI states from the downselected subset. Thecardinality of the BFD set may be constrained to be smaller than M(e.g., 2). As such, UE 115-a may consult a set of rules to determinewhich reference signals of the TCI states of the downselected subset theBFD set is to include (e.g., which 2 TCI states of the 8 MAC-CEdownselected TCI states are to be included).

For instance, UE 115-a may determine the M reference signals based on anorder (e.g., ascending or descending order) of the TCI states of thedownselected subset. For instance, if TCI states with IDs 4, 8, 15, 16,23, and 42 are included in the downselected subset and assuming M=2, UE115-a may determine that reference signals from TCI states 4 and 8 orthat reference signals from TCI states 23 and 42 are to be included inthe BFD set. Additionally or alternatively, if two reference signals arepresent in a TCI state whose reference signal is to be included in a BFDset, a reference signal may be chosen based on the QCL type thereference signal is associated with. For instance, if UE 115-a is tochoose a reference signal of TCI state 4 for the BFD set and TCI state 4includes 2 reference signals, UE 115-a may choose the reference signalassociated with QCL type D. Additionally or alternatively, any referencesignals among the TCI states of the downselected subset which arerepeats of another reference signal among the TCI state of thedownselected subset may be removed from consideration, which may leaveone copy left for consideration. Additionally or alternatively, UE 115-amay choose the M reference signals from the downselected subset of TCIstates with the lowest periodicity. Additionally or alternatively, UE115-a may choose the M reference signals from the downselected subset ofTCI states with the largest RSRP.

FIG. 3 illustrates an example of a cross-carrier configuration 300 thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. In some examples, cross-carrier configuration 300 mayimplement aspects of wireless communications systems 100 and/or 200. Forinstance, cross-carrier configuration may be a configuration of a UE 115and/or a base station 105 as described with reference to FIGS. 1 and/or2 .

Cross carrier configuration 300 may include a first component carrier,C1 305, and a second component carrier, C2 310. C1 305 may be at a lowerfrequency range than C2 310. Additionally or alternatively, C1 305 mayrepresent a sub-6 GHz band (e.g., FR1) and C2 310 may represent a bandabove 6 GHz (e.g., FR2). C1 305 may carry one or more PDCCHtransmissions 315 and C2 310 may carry one or more PDSCH transmissions320. Each PDCCH transmission 315 may schedule a corresponding PDSCHtransmission 320. For instance, PDCCH transmission 315-a may schedulePDSCH transmission 320-a and PDCCH transmission 315-b may schedule PDSCHtransmission 320-b. A UE 115 may receive PDSCH transmission 320-a afterthreshold time window 325-a has elapsed and may receive PDSCHtransmission 320-b before threshold time window 325-b has elapsed. Insome cases, all of PDSCH transmission 320-b may be contained withthreshold time window 325-b. In other cases, a portion of PDSCHtransmission 320-b may be received within threshold time window 325-band a portion may be received after. Although each threshold time window325 is drawn starting from an end of a PDCCH transmission 315, thresholdtime window 325 may, alternatively, be defined to start at the beginningor anywhere within the time spanned by a corresponding PDCCHtransmission 315.

After a UE 115 receives PDCCH transmission 315-a, the UE 115 may processPDCCH transmission 315-a over threshold time window 325-a. Uponprocessing PDCCH transmission 315-a, the UE 115 may obtain informationrelated to a default beam. After obtaining the default beam information,UE 115 may use the default beam to receive PDSCH transmission 320-a.After the UE 115 receives PDCCH transmission 315-b, the UE 115 may beginprocessing PDCCH transmission 315-b. However, the UE 115 may beginreceiving PDSCH transmission 320-b before threshold time window 325-bhas elapsed. As such, the UE 115 may use the default beam that the UE115 used to receive PDSCH transmission 320-a to receive PDSCHtransmission 320-b. Upon processing PDCCH transmission 315-b, the UE 115may update the default beam in line with the default beam information ofPDCCH transmission 315-b. If the next PDSCH transmission 320 is receivedbefore a next threshold time window 325 after a next PDCCH transmission315, the UE 115 may use the updated default beam to receive the nextPDSCH transmission 320. Elsewise, the UE 115 may use the default beamspecified by the next PDCCH transmission 315.

FIG. 4 illustrates an example of a cross-carrier configuration 400 thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. In some examples, cross-carrier configuration 400 mayimplement aspects of wireless communications systems 100 and/or 200. Forinstance, cross-carrier configuration may be a configuration of a UE 115and/or a base station 105 as described with reference to FIGS. 1 and/or2 .

Cross carrier configuration 400 may include a first component carrier,C1 405, and a second component carrier, C2 410. C1 405 may be at a lowerfrequency range than C2 410. Additionally or alternatively, C1 405 mayrepresent a sub-6 GHz band (e.g., FR1) and C2 410 may represent a bandabove 6 GHz (e.g., FR2). C1 405 may carry one or more PDCCHtransmissions 415 and C2 410 may carry one or more PDSCH transmissions420. Each PDCCH transmission 415 may schedule a corresponding PDSCHtransmission 420. For instance, PDCCH transmission 415-a may schedulePDSCH transmission 420-a and PDCCH transmission 415-b may schedule PDSCHtransmission 420-b. A UE 115 may receive PDSCH transmission 420-a afterthreshold time window 425-a has elapsed and may receive PDSCHtransmission 420-b before threshold time window 425-b has elapsed. Insome cases, all of PDSCH transmission 420-b may be contained withthreshold time window 425-b. In other cases, a portion of PDSCHtransmission 420-b may be received within threshold time window 425-band a portion may be received after. Although each threshold time window425 is drawn starting from an end of a PDCCH transmission 415, thresholdtime window 425 may, alternatively, be defined to start at the beginningor anywhere within the time spanned by a corresponding PDCCHtransmission 415.

Additionally or alternatively, C1 405 may carry feedback information430, which may consist of an ACK (e.g., if the UE 115 successfullydecoded PDSCH transmission 420-a) or a NACK (e.g., if the UE 115 failedto decode PDSCH transmission 420-a). A threshold time window 435 mayoccur between receiving PDSCH transmission 420-a and transmittingfeedback information 430. Although each threshold time window 435 isdrawn starting from an end of a PDSCH transmission 420, threshold timewindow 435 may, alternatively, be defined to start at the beginning oranywhere within the time spanned by a corresponding PDSCH transmission420. Additionally or alternatively, although each threshold time window435 is drawn ending from an end of feedback information 430, thresholdtime window 435 may, alternatively, be defined to end at the beginningor anywhere within the time spanned by feedback information 430.

After a UE 115 receives PDCCH transmission 415-a, the UE 115 may processPDCCH transmission 415-a over threshold time window 425-a. Uponprocessing PDCCH transmission 415-a, the UE 115 may obtain informationrelated to a default beam. After obtaining the default beam information,UE 115 may use the default beam to receive PDSCH transmission 420-a. UE115 may attempt to decode PDSCH transmission 420-a over threshold timewindow 435 and may transmit feedback information 430. After transmittingfeedback information 430, the UE 115 may receive and begin processingPDCCH transmission 415-b. However, the UE 115 may begin receiving PDSCHtransmission 420-b before threshold time window 425-b has elapsed. Assuch, the UE 115 may use the default beam that the UE 115 used toreceive PDSCH transmission 420-a to receive PDSCH transmission 420-b.Upon processing PDCCH transmission 425-b, the UE 115 may update thedefault beam in line with the default beam information of PDCCHtransmission 415-b. If the next PDSCH transmission 420 is receivedbefore a next threshold time window 425 after a next PDCCH transmission415, the UE 115 may use the updated default beam to receive the nextPDSCH transmission 420. Elsewise, the UE 115 may use the default beamspecified by the next PDCCH transmission 415.

FIG. 5 illustrates an example of a process flow 500 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. In someexamples, process flow 500 may implement aspects of wirelesscommunications systems 100 and/or 200. For instance, process flow 500may include UE 115-b and base station 105-b, which may be examples ofaspects of a UE 115 and a base station 105, respectively, as describedwith reference to FIGS. 1 and/or 2 .

At 505, base station 105-b may transmit, over a first component carrier(e.g., FR1), a first PDCCH transmission for a first PDSCH transmissionover a second component carrier (e.g., FR2). UE 115-b may receive thefirst PDCCH transmission. In some cases, base station 105-b may transmitan indication of a first beam as a default beam for the first PDSCHtransmission, where the indication of the first beam may be received inconnection with the first PDCCH transmission or an RRC message. If theindication is in connection with the first PDCCH transmission, UE 115-bmay receive the indication by decoding or otherwise processing the firstPDCCH transmission.

At 510, base station 105-b may transmit the first PDSCH transmissionover the second component carrier. UE 115-b may receive the first PDSCHtransmission using a first beam as a default beam, such as the firstbeam indicated by the transmitted indication.

At 515, base station 105-b may transmit, over the first componentcarrier, a second PDCCH transmission for a second PDSCH transmissionover the second component carrier. UE 115-b may receive the second PDCCHtransmission.

At 520, UE 115-b may select the first beam as the default beam for thesecond PDSCH transmission. UE 115-b may make such a selection based on areceive time of the second PDSCH transmission occurring within a firstthreshold time window following the second PDCCH transmission. The firstthreshold time window may be, for instance, a time to process the secondPDCCH transmission. In some cases, a receive time of the first PDSCHtransmission may occur outside of the first threshold time window. Insome cases, UE 115-b may determine that a receive time of the secondPDCCH transmission occurs after a second threshold time window followinga receive time of the first PDSCH transmission. Additionally oralternatively, UE 115-b may transmit feedback information (e.g., an ACKor NACK) for the first PDSCH transmission. In some cases, the secondthreshold window may be a time duration between a receive time of thePDSCH transmission to a transmit time of the feedback information.

At 525, base station 105-b may transmit the second PDSCH transmissionover the second component carrier using the first beam as the defaultbeam. UE 115-b may receive the second PDSCH transmission based on thesecond PDCCH transmission.

FIG. 6 illustrates an example of a process flow 600 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. In someexamples, process flow 600 may implement aspects of wirelesscommunications systems 100 and/or 200. For instance, process flow 600may include UE 115-c and base station 105-c, which may be examples ofaspects of a UE 115 and a base station 105, respectively, as describedwith reference to FIGS. 1 and/or 2 .

At 605, base station 105-c may transmit a configuration message (e.g., aMAC-CE) indicating a set of TCI states for downlink PDSCH transmissions.UE 115-c may receive the configuration message.

At 610, UE 115-c may identify one or more reference signals (e.g., CRS,DM-RS, CSI-RS) to monitor for BFD. UE 115-c may identify the one or moresignals based on the indicated set of TCI states. For instance, UE 115-cmay update a BFD set that is to contain the one or more referencesignals. In on example, UE 115-c may identify a reference signal type(e.g., a CRS, DM-RS, CSI-RS) associated with each TCI state in the setof TCI states and may select, from the set of TCI states, a subset ofTCI states for BFD based on the reference signal type associated witheach TCI state of the set of TCI states. In some cases, UE 115-c maydetermine that a TCI state in the set of TCI states is associated withmultiple reference signal types and may select, based on an entryassociated with the TCI state (e.g., a QCL type, such as Type D), one ofthe reference signal types associated with the TCI state (e.g., for usein selecting the subset of TCI states. In some cases, selecting thesubset of TCI states includes determining an ascending or descendingorder of TCI states (e.g., TCI states with IDs 4, 8, 15, 16, 23, 42) inthe set of TCI states and identifying a fixed number of TCI states forthe subset of TCI states based on the ascending (e.g., TCI state with ID4 may be chosen) or descending order (e.g., TCI state with ID 42 may bechosen). In some cases, the one or more reference signals may beidentified based on an amount of repetition of a given reference signaltype during the PDSCH transmissions, a periodicity of a given referencesignal type, a receive power associated with a reference signal type, ora combination of these.

At 615, UE 115-c may identify one or more BFD detection beams. UE 115-cmay identify the one or more BFD detection beams based on the identifiedTCI states and the identified one or more reference signals.

At 620, UE 115-c may monitor the identified one or more referencesignals using the identified one or more beam failure detection beams.

At 625, UE 115-c may selectively trigger a beam failure reportingprocedure (e.g., beam recovery) based on the monitoring.

FIG. 7 shows a block diagram 700 of a device 705 that supports defaultbeam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Thedevice 705 may be an example of aspects of a UE 115 as described herein.The device 705 may include a receiver 710, a communications manager 715,and a transmitter 720. The device 705 may also include a processor. Eachof these components may be in communication with one another (e.g., viaone or more buses).

The receiver 710 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to default beamidentification and beam failure detection for cross carrier scheduling,etc.). Information may be passed on to other components of the device705. The receiver 710 may be an example of aspects of the transceiver1020 described with reference to FIG. 10 . The receiver 710 may utilizea single antenna or a set of antennas.

The communications manager 715 may receive, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier, receive, over the first component carrier, asecond downlink grant for a second data transmission over the secondcomponent carrier, receive the first data transmission over the secondcomponent carrier using a first beam as a default beam, receive, basedon the second downlink grant, the second data transmission over thesecond component carrier using the first beam as the default beam, andselect the first beam as the default beam for the second datatransmission based on a receive time of the second data transmissionoccurring within a first threshold time window following the seconddownlink grant. The communications manager 715 may also receive aconfiguration message indicating a set of TCI states for downlink datatransmissions to the UE, identify one or more reference signals tomonitor for beam failure detection based on the indicated set of TCIstates, identify one or more beam failure detection beams based on theindicated set of TCI states and the identified one or more referencesignals, monitor the identified one or more reference signals using theidentified one or more beam failure detection beams, and selectivelytrigger a beam failure reporting procedure based on the monitoring. Thecommunications manager 715 may be an example of aspects of thecommunications manager 1010 or the UE communications manager 150described herein.

The communications manager 715, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 715, or itssub-components may be executed by a general-purpose processor, a digitalsignal processor (DSP), an application-specific integrated circuit(ASIC), a field-programmable gate array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed in the present disclosure.

The communications manager 715, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the communicationsmanager 715, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the communications manager 715, or its sub-components,may be combined with one or more other hardware components, includingbut not limited to an input/output (I/O) component, a transceiver, anetwork server, another computing device, one or more other componentsdescribed in the present disclosure, or a combination thereof inaccordance with various aspects of the present disclosure.

The transmitter 720 may transmit signals generated by other componentsof the device 705. In some examples, the transmitter 720 may becollocated with a receiver 710 in a transceiver module. For example, thetransmitter 720 may be an example of aspects of the transceiver 1020described with reference to FIG. 10 . The transmitter 720 may utilize asingle antenna or a set of antennas.

FIG. 8 shows a block diagram 800 of a device 805 that supports defaultbeam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Thedevice 805 may be an example of aspects of a device 705, or a UE 115 asdescribed herein. The device 805 may include a receiver 810, acommunications manager 815, and a transmitter 860. The device 805 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 810 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to default beamidentification and beam failure detection for cross carrier scheduling,etc.). Information may be passed on to other components of the device805. The receiver 810 may be an example of aspects of the transceiver1020 described with reference to FIG. 10 . The receiver 810 may utilizea single antenna or a set of antennas.

The communications manager 815 may be an example of aspects of thecommunications manager 715 as described herein. The communicationsmanager 815 may include a downlink grant receiver 820, a datatransmission receiver 825, an UE beam selector 830, a configurationmessage receiver 835, a reference signal identifier 840, a beamidentifier 845, a reference signal monitoring component 850, and a beamfailure trigger component 855. The communications manager 815 may be anexample of aspects of the communications manager 1010 or the UEcommunications manager 150 described herein.

The downlink grant receiver 820 may receive, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier and receive, over the first component carrier,a second downlink grant for a second data transmission over the secondcomponent carrier.

The data transmission receiver 825 may receive the first datatransmission over the second component carrier using a first beam as adefault beam and receive, based on the second downlink grant, the seconddata transmission over the second component carrier using the first beamas the default beam.

The UE beam selector 830 may select the first beam as the default beamfor the second data transmission based on a receive time of the seconddata transmission occurring within a first threshold time windowfollowing the second downlink grant.

The configuration message receiver 835 may receive a configurationmessage indicating a set of TCI states for downlink data transmissionsto the UE.

The reference signal identifier 840 may identify one or more referencesignals to monitor for beam failure detection based on the indicated setof TCI states.

The beam identifier 845 may identify one or more beam failure detectionbeams based on the indicated set of TCI states and the identified one ormore reference signals.

The reference signal monitoring component 850 may monitor the identifiedone or more reference signals using the identified one or more beamfailure detection beams.

The beam failure trigger component 855 may selectively trigger a beamfailure reporting procedure based on the monitoring.

The transmitter 860 may transmit signals generated by other componentsof the device 805. In some examples, the transmitter 860 may becollocated with a receiver 810 in a transceiver module. For example, thetransmitter 860 may be an example of aspects of the transceiver 1020described with reference to FIG. 10 . The transmitter 860 may utilize asingle antenna or a set of antennas.

FIG. 9 shows a block diagram 900 of a communications manager 905 thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. The communications manager 905 may be an example of aspectsof a communications manager 715, a communications manager 815, or acommunications manager 1010 or the UE communications manager 150described herein. The communications manager 905 may include a downlinkgrant receiver 910, a data transmission receiver 915, an UE beamselector 920, a beam indication receiver 925, an UE time windowdeterminer 930, a threshold time window determiner 935, a configurationmessage receiver 940, a reference signal identifier 945, a beamidentifier 950, a reference signal monitoring component 955, a beamfailure trigger component 960, and a TCI state selector 965. Each ofthese modules may communicate, directly or indirectly, with one another(e.g., via one or more buses).

The downlink grant receiver 910 may receive, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier. In some examples, the downlink grant receiver910 may receive, over the first component carrier, a second downlinkgrant for a second data transmission over the second component carrier.

The data transmission receiver 915 may receive the first datatransmission over the second component carrier using a first beam as adefault beam. In some examples, the data transmission receiver 915 mayreceive, based on the second downlink grant, the second datatransmission over the second component carrier using the first beam asthe default beam.

The UE beam selector 920 may select the first beam as the default beamfor the second data transmission based on a receive time of the seconddata transmission occurring within a first threshold time windowfollowing the second downlink grant.

The beam indication receiver 925 may receive an indication of the firstbeam as the default beam for the first data transmission. In some cases,the indication of the first beam is received in connection with thefirst downlink grant. In some cases, a receive time of the first datatransmission occurs outside of the first threshold time window followingthe first downlink grant. In some cases, the indication of the firstbeam is received in connection with a RRC message.

The UE time window determiner 930 may determine that a receive time ofthe second downlink grant occurs after a second threshold time windowfollowing a receive time of the first data transmission, where selectingthe first beam as the default beam is further based on thedetermination.

The threshold time window determiner 935 may transmit feedbackinformation for the first data transmission, where the second thresholdtime window is defined based on a transmit time of the feedbackinformation.

The configuration message receiver 940 may receive a configurationmessage indicating a set of TCI states for downlink data transmissionsto the UE.

The reference signal identifier 945 may identify one or more referencesignals to monitor for beam failure detection based on the indicated setof TCI states. In some examples, the reference signal identifier 945 mayidentify a reference signal type associated with each TCI state in theset of TCI states. In some examples, the reference signal identifier 945may determine that a TCI state in the set of TCI states is associatedwith multiple reference signal types. In some examples, the referencesignal identifier 945 may select, based on an entry associated with theTCI state, one of the reference signal types associated with the TCIstate for use in selecting the subset of TCI states. In some examples,the reference signal identifier 945 may identify the one or morereference signals is further based on an amount of repetition for agiven reference signal type during the downlink data transmissions. Insome examples, the reference signal identifier 945 may identify the oneor more reference signals is further based on a periodicity of a givenreference signal type during the downlink data transmissions. In someexamples, the reference signal identifier 945 may identify the one ormore reference signals is further based on a receive power associatedwith a given reference signal type. In some cases, the entry associatedwith the TCI state is a Type D entry of the TCI state.

The beam identifier 950 may identify one or more beam failure detectionbeams based on the indicated set of TCI states and the identified one ormore reference signals.

The reference signal monitoring component 955 may monitor the identifiedone or more reference signals using the identified one or more beamfailure detection beams.

The beam failure trigger component 960 may selectively trigger a beamfailure reporting procedure based on the monitoring.

The TCI state selector 965 may select, from the set of TCI states, asubset of TCI states for beam failure detection based on the referencesignal type associated with each TCI state of the set of TCI states. Insome examples, the TCI state selector 965 may determine an ascending ordescending order of TCI states in the set of TCI states. In someexamples, the TCI state selector 965 may identify a fixed number of TCIstates for the subset of TCI states based on the ascending or descendingorder.

FIG. 10 shows a diagram of a system 1000 including a device 1005 thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. The device 1005 may be an example of or include thecomponents of device 705, device 805, or a UE 115 as described herein.The device 1005 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including a communications manager 1010, an I/Ocontroller 1015, a transceiver 1020, an antenna 1025, memory 1030, and aprocessor 1040. These components may be in electronic communication viaone or more buses (e.g., bus 1045).

The communications manager 1010 may receive, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier, receive, over the first component carrier, asecond downlink grant for a second data transmission over the secondcomponent carrier, receive the first data transmission over the secondcomponent carrier using a first beam as a default beam, receive, basedon the second downlink grant, the second data transmission over thesecond component carrier using the first beam as the default beam, andselect the first beam as the default beam for the second datatransmission based on a receive time of the second data transmissionoccurring within a first threshold time window following the seconddownlink grant. The communications manager 1010 may also receive aconfiguration message indicating a set of TCI states for downlink datatransmissions to the UE, identify one or more reference signals tomonitor for beam failure detection based on the indicated set of TCIstates, identify one or more beam failure detection beams based on theindicated set of TCI states and the identified one or more referencesignals, monitor the identified one or more reference signals using theidentified one or more beam failure detection beams, and selectivelytrigger a beam failure reporting procedure based on the monitoring.

The I/O controller 1015 may manage input and output signals for thedevice 1005. The I/O controller 1015 may also manage peripherals notintegrated into the device 1005. In some cases, the I/O controller 1015may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 1015 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 1015may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 1015may be implemented as part of a processor. In some cases, a user mayinteract with the device 1005 via the I/O controller 1015 or viahardware components controlled by the I/O controller 1015.

The transceiver 1020 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1020 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1020 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1025.However, in some cases the device may have more than one antenna 1025,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1030 may include random-access memory (RAM) and read-onlymemory (ROM). The memory 1030 may store computer-readable,computer-executable code 1035 including instructions that, whenexecuted, cause the processor to perform various functions describedherein. In some cases, the memory 1030 may contain, among other things,a basic input/output system (BIOS) which may control basic hardware orsoftware operation such as the interaction with peripheral components ordevices.

The processor 1040 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1040 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 1040. The processor 1040 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 1030) to cause the device 1005 to perform variousfunctions (e.g., functions or tasks supporting default beamidentification and beam failure detection for cross carrier scheduling).

The code 1035 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1035 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1035 may not be directly executable by theprocessor 1040 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 11 shows a block diagram 1100 of a device 1105 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Thedevice 1105 may be an example of aspects of a base station 105 asdescribed herein. The device 1105 may include a receiver 1110, acommunications manager 1115, and a transmitter 1120. The device 1105 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 1110 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to default beamidentification and beam failure detection for cross carrier scheduling,etc.). Information may be passed on to other components of the device1105. The receiver 1110 may be an example of aspects of the transceiver1420 described with reference to FIG. 14 . The receiver 1110 may utilizea single antenna or a set of antennas.

The communications manager 1115 may transmit, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier, transmit, over the first component carrier, asecond downlink grant for a second data transmission over the secondcomponent carrier, transmit the first data transmission over the secondcomponent carrier using a first beam as a default beam, transmit, basedon the second downlink grant, the second data transmission over thesecond component carrier using the first beam as the default beam, andselect the first beam as the default beam for the second datatransmission based on a receive time of the second data transmissionoccurring within a first threshold time window following the seconddownlink grant. The communications manager 1115 may be an example ofaspects of the communications manager 1410 or the base stationcommunications manager 140 described herein.

The communications manager 1115, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1115, or itssub-components may be executed by a general-purpose processor, a DSP, anASIC, a FPGA or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described in the presentdisclosure.

The communications manager 1115, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1115, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1115, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

The transmitter 1120 may transmit signals generated by other componentsof the device 1105. In some examples, the transmitter 1120 may becollocated with a receiver 1110 in a transceiver module. For example,the transmitter 1120 may be an example of aspects of the transceiver1420 described with reference to FIG. 14 . The transmitter 1120 mayutilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a device 1205 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Thedevice 1205 may be an example of aspects of a device 1105, or a basestation 105 as described herein. The device 1205 may include a receiver1210, a communications manager 1215, and a transmitter 1235. The device1205 may also include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 1210 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to default beamidentification and beam failure detection for cross carrier scheduling,etc.). Information may be passed on to other components of the device1205. The receiver 1210 may be an example of aspects of the transceiver1420 described with reference to FIG. 14 . The receiver 1210 may utilizea single antenna or a set of antennas.

The communications manager 1215 may be an example of aspects of thecommunications manager 1115 as described herein. The communicationsmanager 1215 may include a downlink grant transmitter 1220, a datatransmission transmitter 1225, and a base station beam selector 1230.The communications manager 1215 may be an example of aspects of thecommunications manager 1410 or the base station communications manager140 described herein.

The downlink grant transmitter 1220 may transmit, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier and transmit, over the first component carrier,a second downlink grant for a second data transmission over the secondcomponent carrier.

The data transmission transmitter 1225 may transmit the first datatransmission over the second component carrier using a first beam as adefault beam and transmit, based on the second downlink grant, thesecond data transmission over the second component carrier using thefirst beam as the default beam.

The base station beam selector 1230 may select the first beam as thedefault beam for the second data transmission based on a receive time ofthe second data transmission occurring within a first threshold timewindow following the second downlink grant.

The transmitter 1235 may transmit signals generated by other componentsof the device 1205. In some examples, the transmitter 1235 may becollocated with a receiver 1210 in a transceiver module. For example,the transmitter 1235 may be an example of aspects of the transceiver1420 described with reference to FIG. 14 . The transmitter 1235 mayutilize a single antenna or a set of antennas.

FIG. 13 shows a block diagram 1300 of a communications manager 1305 thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. The communications manager 1305 may be an example of aspectsof a communications manager 1115, a communications manager 1215, or acommunications manager 1410 or the base station communications manager140 described herein. The communications manager 1305 may include adownlink grant transmitter 1310, a data transmission transmitter 1315, abase station beam selector 1320, a beam indication transmitter 1325, anda base station time window determiner 1330. Each of these modules maycommunicate, directly or indirectly, with one another (e.g., via one ormore buses).

The downlink grant transmitter 1310 may transmit, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier. In some examples, the downlink granttransmitter 1310 may transmit, over the first component carrier, asecond downlink grant for a second data transmission over the secondcomponent carrier.

The data transmission transmitter 1315 may transmit the first datatransmission over the second component carrier using a first beam as adefault beam. In some examples, the data transmission transmitter 1315may transmit, based on the second downlink grant, the second datatransmission over the second component carrier using the first beam asthe default beam.

The base station beam selector 1320 may select the first beam as thedefault beam for the second data transmission based on a receive time ofthe second data transmission occurring within a first threshold timewindow following the second downlink grant.

The beam indication transmitter 1325 may transmit an indication of thefirst beam as the default beam for the first data transmission. In somecases, the indication of the first beam is transmitted in connectionwith the first downlink grant. In some cases, a receive time of thefirst data transmission occurs outside of the first threshold timewindow following the first downlink grant. In some cases, the indicationof the first beam is transmitted in connection with a RRC message.

The base station time window determiner 1330 may determine that areceive time of the second downlink grant occurs after a secondthreshold time window following a receive time of the first datatransmission, where selecting the first beam as the default beam isfurther based on the determination. In some examples, the base stationtime window determiner 1330 may receive feedback information for thefirst data transmission, where the second threshold time window isdefined based on a transmit time of the feedback information.

FIG. 14 shows a diagram of a system 1400 including a device 1405 thatsupports default beam identification and beam failure detection forcross carrier scheduling in accordance with aspects of the presentdisclosure. The device 1405 may be an example of or include thecomponents of device 1105, device 1205, or a base station 105 asdescribed herein. The device 1405 may include components forbi-directional voice and data communications including components fortransmitting and receiving communications, including a communicationsmanager 1410, a network communications manager 1415, a transceiver 1420,an antenna 1425, memory 1430, a processor 1440, and an inter-stationcommunications manager 1445. These components may be in electroniccommunication via one or more buses (e.g., bus 1450).

The communications manager 1410 may transmit, over a first componentcarrier, a first downlink grant for a first data transmission over asecond component carrier, transmit, over the first component carrier, asecond downlink grant for a second data transmission over the secondcomponent carrier, transmit the first data transmission over the secondcomponent carrier using a first beam as a default beam, transmit, basedon the second downlink grant, the second data transmission over thesecond component carrier using the first beam as the default beam, andselect the first beam as the default beam for the second datatransmission based on a receive time of the second data transmissionoccurring within a first threshold time window following the seconddownlink grant.

The network communications manager 1415 may manage communications withthe core network (e.g., via one or more wired backhaul links). Forexample, the network communications manager 1415 may manage the transferof data communications for client devices, such as one or more UEs 115.

The transceiver 1420 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1420 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1420 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1425.However, in some cases the device may have more than one antenna 1425,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1430 may include RAM, ROM, or a combination thereof. Thememory 1430 may store computer-readable code 1435 including instructionsthat, when executed by a processor (e.g., the processor 1440) cause thedevice to perform various functions described herein. In some cases, thememory 1430 may contain, among other things, a BIOS which may controlbasic hardware or software operation such as the interaction withperipheral components or devices.

The processor 1440 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1440 may be configured to operate a memoryarray using a memory controller. In some cases, a memory controller maybe integrated into processor 1440. The processor 1440 may be configuredto execute computer-readable instructions stored in a memory (e.g., thememory 1430) to cause the device 1405 to perform various functions(e.g., functions or tasks supporting default beam identification andbeam failure detection for cross carrier scheduling).

The inter-station communications manager 1445 may manage communicationswith other base station 105, and may include a controller or schedulerfor controlling communications with UEs 115 in cooperation with otherbase stations 105. For example, the inter-station communications manager1445 may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, the inter-station communications manager1445 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

The code 1435 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1435 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1435 may not be directly executable by theprocessor 1440 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 15 shows a flowchart illustrating a method 1500 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Theoperations of method 1500 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1500 may be performed by a communications manager as described withreference to FIGS. 7 through 10 . In some examples, a UE may execute aset of instructions to control the functional elements of the UE toperform the functions described below. Additionally or alternatively, aUE may perform aspects of the functions described below usingspecial-purpose hardware.

At 1505, the UE may receive, over a first component carrier, a firstdownlink grant for a first data transmission over a second componentcarrier. The operations of 1505 may be performed according to themethods described herein. In some examples, aspects of the operations of1505 may be performed by a downlink grant receiver as described withreference to FIGS. 7 through 10 .

At 1510, the UE may receive the first data transmission over the secondcomponent carrier using a first beam as a default beam. The operationsof 1510 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1510 may be performed by adata transmission receiver as described with reference to FIGS. 7through 10 .

At 1515, the UE may receive, over the first component carrier, a seconddownlink grant for a second data transmission over the second componentcarrier. The operations of 1515 may be performed according to themethods described herein. In some examples, aspects of the operations of1515 may be performed by a downlink grant receiver as described withreference to FIGS. 7 through 10 .

At 1520, the UE may select the first beam as the default beam for thesecond data transmission based on a receive time of the second datatransmission occurring within a first threshold time window followingthe second downlink grant. The operations of 1520 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1520 may be performed by an UE beam selector asdescribed with reference to FIGS. 7 through 10 .

At 1525, the UE may receive, based on the second downlink grant, thesecond data transmission over the second component carrier using thefirst beam as the default beam. The operations of 1525 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1525 may be performed by a data transmission receiveras described with reference to FIGS. 7 through 10 .

FIG. 16 shows a flowchart illustrating a method 1600 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Theoperations of method 1600 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1600 may be performed by a communications manager as described withreference to FIGS. 7 through 10 . In some examples, a UE may execute aset of instructions to control the functional elements of the UE toperform the functions described below. Additionally or alternatively, aUE may perform aspects of the functions described below usingspecial-purpose hardware.

At 1605, the UE may receive, over a first component carrier, a firstdownlink grant for a first data transmission over a second componentcarrier. The operations of 1605 may be performed according to themethods described herein. In some examples, aspects of the operations of1605 may be performed by a downlink grant receiver as described withreference to FIGS. 7 through 10 .

At 1610, the UE may receive an indication of the first beam as thedefault beam for the first data transmission. The operations of 1610 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 1610 may be performed by a beamindication receiver as described with reference to FIGS. 7 through 10 .

At 1615, the UE may receive the first data transmission over the secondcomponent carrier using a first beam as a default beam. The operationsof 1615 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1615 may be performed by adata transmission receiver as described with reference to FIGS. 7through 10 .

At 1620, the UE may receive, over the first component carrier, a seconddownlink grant for a second data transmission over the second componentcarrier. The operations of 1620 may be performed according to themethods described herein. In some examples, aspects of the operations of1620 may be performed by a downlink grant receiver as described withreference to FIGS. 7 through 10 .

At 1625, the UE may select the first beam as the default beam for thesecond data transmission based on a receive time of the second datatransmission occurring within a first threshold time window followingthe second downlink grant. The operations of 1625 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1625 may be performed by an UE beam selector asdescribed with reference to FIGS. 7 through 10 .

At 1630, the UE may receive, based on the second downlink grant, thesecond data transmission over the second component carrier using thefirst beam as the default beam. The operations of 1630 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1630 may be performed by a data transmission receiveras described with reference to FIGS. 7 through 10 .

FIG. 17 shows a flowchart illustrating a method 1700 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Theoperations of method 1700 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1700 may be performed by a communications manager as described withreference to FIGS. 7 through 10 . In some examples, a UE may execute aset of instructions to control the functional elements of the UE toperform the functions described below. Additionally or alternatively, aUE may perform aspects of the functions described below usingspecial-purpose hardware.

At 1705, the UE may receive, over a first component carrier, a firstdownlink grant for a first data transmission over a second componentcarrier. The operations of 1705 may be performed according to themethods described herein. In some examples, aspects of the operations of1705 may be performed by a downlink grant receiver as described withreference to FIGS. 7 through 10 .

At 1710, the UE may receive the first data transmission over the secondcomponent carrier using a first beam as a default beam. The operationsof 1710 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1710 may be performed by adata transmission receiver as described with reference to FIGS. 7through 10 .

At 1715, the UE may receive, over the first component carrier, a seconddownlink grant for a second data transmission over the second componentcarrier. The operations of 1715 may be performed according to themethods described herein. In some examples, aspects of the operations of1715 may be performed by a downlink grant receiver as described withreference to FIGS. 7 through 10 .

At 1720, the UE may determine that a receive time of the second downlinkgrant occurs after a second threshold time window following a receivetime of the first data transmission. The operations of 1720 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1720 may be performed by an UE beamselector as described with reference to FIGS. 7 through 10 .

At 1725, the UE may select the first beam as the default beam for thesecond data transmission based on a receive time of the second datatransmission occurring within a first threshold time window followingthe second downlink grant and determining that the receive time of thesecond downlink grant occurs after the second threshold window. Theoperations of 1725 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1725 may beperformed by an UE time window determiner as described with reference toFIGS. 7 through 10 .

At 1730, the UE may receive, based on the second downlink grant, thesecond data transmission over the second component carrier using thefirst beam as the default beam. The operations of 1730 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1730 may be performed by a data transmission receiveras described with reference to FIGS. 7 through 10 .

FIG. 18 shows a flowchart illustrating a method 1800 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Theoperations of method 1800 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1800 may be performed by a communications manager as described withreference to FIGS. 7 through 10 . In some examples, a UE may execute aset of instructions to control the functional elements of the UE toperform the functions described below. Additionally or alternatively, aUE may perform aspects of the functions described below usingspecial-purpose hardware.

At 1805, the UE may receive a configuration message indicating a set ofTCI states for downlink data transmissions to the UE. The operations of1805 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1805 may be performed by aconfiguration message receiver as described with reference to FIGS. 7through 10 .

At 1810, the UE may identify one or more reference signals to monitorfor beam failure detection based on the indicated set of TCI states. Theoperations of 1810 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1810 may beperformed by a reference signal identifier as described with referenceto FIGS. 7 through 10 .

At 1815, the UE may identify one or more beam failure detection beamsbased on the indicated set of TCI states and the identified one or morereference signals. The operations of 1815 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1815 may be performed by a beam identifier as describedwith reference to FIGS. 7 through 10 .

At 1820, the UE may monitor the identified one or more reference signalsusing the identified one or more beam failure detection beams. Theoperations of 1820 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1820 may beperformed by a reference signal monitoring component as described withreference to FIGS. 7 through 10 .

At 1825, the UE may selectively trigger a beam failure reportingprocedure based on the monitoring. The operations of 1825 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1825 may be performed by a beam failuretrigger component as described with reference to FIGS. 7 through 10 .

FIG. 19 shows a flowchart illustrating a method 1900 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Theoperations of method 1900 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1900 may be performed by a communications manager as described withreference to FIGS. 7 through 10 . In some examples, a UE may execute aset of instructions to control the functional elements of the UE toperform the functions described below. Additionally or alternatively, aUE may perform aspects of the functions described below usingspecial-purpose hardware.

At 1905, the UE may receive a configuration message indicating a set ofTCI states for downlink data transmissions to the UE. The operations of1905 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1905 may be performed by aconfiguration message receiver as described with reference to FIGS. 7through 10 .

At 1910, the UE may identify a reference signal type associated witheach TCI state in the set of TCI states. The operations of 1910 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1910 may be performed by a reference signalidentifier as described with reference to FIGS. 7 through 10 .

At 1915, the UE may select, from the set of TCI states, a subset of TCIstates for beam failure detection based on the reference signal typeassociated with each TCI state of the set of TCI states. The operationsof 1915 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1915 may be performed by aTCI state selector as described with reference to FIGS. 7 through 10 .

At 1920, the UE may identify one or more reference signals to monitorfor beam failure detection based on the indicated set of TCI states. Theoperations of 1920 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1920 may beperformed by a reference signal identifier as described with referenceto FIGS. 7 through 10 .

At 1925, the UE may identify one or more beam failure detection beamsbased on the indicated set of TCI states and the identified one or morereference signals. The operations of 1925 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1925 may be performed by a beam identifier as describedwith reference to FIGS. 7 through 10 .

At 1930, the UE may monitor the identified one or more reference signalsusing the identified one or more beam failure detection beams. Theoperations of 1930 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1930 may beperformed by a reference signal monitoring component as described withreference to FIGS. 7 through 10 .

At 1935, the UE may selectively trigger a beam failure reportingprocedure based on the monitoring. The operations of 1935 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1935 may be performed by a beam failuretrigger component as described with reference to FIGS. 7 through 10 .

FIG. 20 shows a flowchart illustrating a method 2000 that supportsdefault beam identification and beam failure detection for cross carrierscheduling in accordance with aspects of the present disclosure. Theoperations of method 2000 may be implemented by a base station 105 orits components as described herein. For example, the operations ofmethod 2000 may be performed by a communications manager as describedwith reference to FIGS. 11 through 14 . In some examples, a base stationmay execute a set of instructions to control the functional elements ofthe base station to perform the functions described below. Additionallyor alternatively, a base station may perform aspects of the functionsdescribed below using special-purpose hardware.

At 2005, the base station may transmit, over a first component carrier,a first downlink grant for a first data transmission over a secondcomponent carrier. The operations of 2005 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 2005 may be performed by a downlink grant transmitter asdescribed with reference to FIGS. 11 through 14 .

At 2010, the base station may transmit the first data transmission overthe second component carrier using a first beam as a default beam. Theoperations of 2010 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2010 may beperformed by a data transmission transmitter as described with referenceto FIGS. 11 through 14 .

At 2015, the base station may transmit, over the first componentcarrier, a second downlink grant for a second data transmission over thesecond component carrier. The operations of 2015 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2015 may be performed by a downlink grant transmitteras described with reference to FIGS. 11 through 14 .

At 2020, the base station may select the first beam as the default beamfor the second data transmission based on a receive time of the seconddata transmission occurring within a first threshold time windowfollowing the second downlink grant. The operations of 2020 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2020 may be performed by a base stationbeam selector as described with reference to FIGS. 11 through 14 .

At 2025, the base station may transmit, based on the second downlinkgrant, the second data transmission over the second component carrierusing the first beam as the default beam. The operations of 2025 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2025 may be performed by a datatransmission transmitter as described with reference to FIGS. 11 through14 .

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned herein as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell maybe associated with a lower-powered base station, as compared with amacro cell, and a small cell may operate in the same or different (e.g.,licensed, unlicensed, etc.) frequency bands as macro cells. Small cellsmay include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs with service subscriptionswith the network provider. A femto cell may also cover a smallgeographic area (e.g., a home) and may provide restricted access by UEshaving an association with the femto cell (e.g., UEs in a closedsubscriber group (CSG), UEs for users in the home, and the like). An eNBfor a macro cell may be referred to as a macro eNB. An eNB for a smallcell may be referred to as a small cell eNB, a pico eNB, a femto eNB, ora home eNB. An eNB may support one or multiple (e.g., two, three, four,and the like) cells, and may also support communications using one ormultiple component carriers.

The wireless communications systems described herein may supportsynchronous or asynchronous operation. For synchronous operation, thebase stations may have similar frame timing, and transmissions fromdifferent base stations may be approximately aligned in time. Forasynchronous operation, the base stations may have different frametiming, and transmissions from different base stations may not bealigned in time. The techniques described herein may be used for eithersynchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA, or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude RAM, ROM, electrically erasable programmable ROM (EEPROM), flashmemory, compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include CD, laser disc, optical disc, digital versatile disc (DVD),floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. An apparatus for wireless communication at a userequipment (UE), comprising: a processor, memory coupled to theprocessor; and instructions stored in the memory and executable by theprocessor to cause the apparatus to: receive a configuration messageindicating a set of transmission configuration indicator (TCI) statesfor downlink data transmissions to the UE; identify one or morereference signals to monitor for beam failure detection based at leastin part on the indicated set of TCI states; identify one or more beamfailure detection beams based at least in part on the indicated set ofTCI states and the identified one or more reference signals; monitor theidentified one or more reference signals using the identified one ormore beam failure detection beams; and selectively trigger a beamfailure reporting procedure based at least in part on the monitoring. 2.The apparatus of claim 1, wherein the instructions executable by theprocessor to cause the apparatus to identify the one or more referencesignals to monitor for beam failure detection further comprisesinstructions executable by the processor to cause the apparatus to:determine a reference signal type associated with each TCI state in theset of TCI states; and select, from the set of TCI states, a subset ofTCI states for beam failure detection based at least in part on thereference signal type associated with each TCI state in the set of TCIstates.
 3. The apparatus of claim 2, wherein the instructions executableby the processor to cause the apparatus to determine the referencesignal type associated with each TCI state in the set of TCI statesfurther comprises instructions executable by the processor to cause theapparatus to: determine that a TCI state in the set of TCI states isassociated with multiple reference signal types; and select, based atleast in part on an entry associated with the TCI state, one of thereference signal types associated with the TCI state for use inselecting the subset of TCI states.
 4. The apparatus of claim 3, whereinthe entry associated with the TCI state is a Type D entry of the TCIstate.
 5. The apparatus of claim 2, wherein the instructions executableby the processor to cause the apparatus to select the subset of TCIstates for beam failure detection further comprises instructionsexecutable by the processor to cause the apparatus to: determine anascending or descending order of TCI states in the set of TCI states;and identify a fixed number of TCI states for the subset of TCI statesbased on the ascending or descending order.
 6. The apparatus of claim 1,wherein the instructions executable by the processor to cause theapparatus to identify the one or more reference signals is further basedat least in part on an amount of repetition for a given reference signaltype during the downlink data transmissions.
 7. The apparatus of claim1, wherein the instructions executable by the processor to cause theapparatus to identify the one or more reference signals is further basedat least in part on a periodicity of a given reference signal typeduring the downlink data transmissions.
 8. The apparatus of claim 1,wherein the instructions executable by the processor to cause theapparatus to identify the one or more reference signals is further basedat least in part on a receive power associated with a given referencesignal type.
 9. The apparatus of claim 1, wherein the instructionsexecutable by the processor to cause the apparatus to selectivelytrigger the beam failure reporting procedure further comprisesinstructions executable by the processor to cause the apparatus to:trigger the beam failure reporting procedure when all beams of the beamfailure detection set have a block error rate (BLER) greater than anout-of-sync (OOS) BLER.
 10. A method for wireless communication at auser equipment (UE), comprising: receiving a configuration messageindicating a set of transmission configuration indicator (TCI) statesfor downlink data transmissions to the UE; identifying one or morereference signals to monitor for beam failure detection based at leastin part on the indicated set of TCI states; identifying one or more beamfailure detection beams based at least in part on the indicated set ofTCI states and the identified one or more reference signals; monitoringthe identified one or more reference signals using the identified one ormore beam failure detection beams; and selectively triggering a beamfailure reporting procedure based at least in part on the monitoring.11. The method of claim 10, wherein identifying the one or morereference signals to monitor for beam failure detection comprises:determining a reference signal type associated with each TCI state inthe set of TCI states; and selecting, from the set of TCI states, asubset of TCI states for beam failure detection based at least in parton the reference signal type associated with each TCI state in the setof TCI states.
 12. The method of claim 11, wherein determining thereference signal type associated with each TCI state in the set of TCIstates comprises: determining that a TCI state in the set of TCI statesis associated with multiple reference signal types; and selecting, basedat least in part on an entry associated with the TCI state, one of thereference signal types associated with the TCI state for use inselecting the subset of TCI states.
 13. The method of claim 12, whereinthe entry associated with the TCI state is a Type D entry of the TCIstate.
 14. The method of claim 11, wherein selecting the subset of TCIstates for beam failure detection comprises: determining an ascending ordescending order of TCI states in the set of TCI states; and identifyinga fixed number of TCI states for the subset of TCI states based on theascending or descending order.
 15. The method of claim 10, whereinidentifying the one or more reference signals is further based at leastin part on an amount of repetition for a given reference signal typeduring the downlink data transmissions.
 16. The method of claim 10,wherein identifying the one or more reference signals is further basedat least in part on a periodicity of a given reference signal typeduring the downlink data transmissions.
 17. The method of claim 10,wherein identifying the one or more reference signals is further basedat least in part on a receive power associated with a given referencesignal type.
 18. The method of claim 10, wherein selectively triggeringthe beam failure reporting procedure further comprises: triggering thebeam failure reporting procedure when all beams of the beam failuredetection set have a block error rate (BLER) greater than an out-of-sync(OOS) BLER.
 19. An apparatus for wireless communication at a userequipment (UE), comprising: means for receiving a configuration messageindicating a set of transmission configuration indicator (TCI) statesfor downlink data transmissions to the UE; means for identifying one ormore reference signals to monitor for beam failure detection based atleast in part on the indicated set of TCI states; means for identifyingone or more beam failure detection beams based at least in part on theindicated set of TCI states and the identified one or more referencesignals; means for monitoring the identified one or more referencesignals using the identified one or more beam failure detection beams;and means for selectively triggering a beam failure reporting procedurebased at least in part on the monitoring.
 20. The apparatus of claim 19,wherein identifying the one or more reference signals to monitor forbeam failure detection comprises: means for determining a referencesignal type associated with each TCI state in the set of TCI states; andmeans for selecting, from the set of TCI states, a subset of TCI statesfor beam failure detection based at least in part on the referencesignal type associated with each TCI state in the set of TCI states. 21.The apparatus of claim 20, wherein determining the reference signal typeassociated with each TCI state in the set of TCI states comprises: meansfor determining that a TCI state in the set of TCI states is associatedwith multiple reference signal types; and means for selecting, based atleast in part on an entry associated with the TCI state, one of thereference signal types associated with the TCI state for use inselecting the subset of TCI states.
 22. The apparatus of claim 21,wherein the entry associated with the TCI state is a Type D entry of theTCI state.
 23. The apparatus of claim 20, wherein the means forselecting the subset of TCI states for beam failure detection comprises:means for determining an ascending or descending order of TCI states inthe set of TCI states; and means for identifying a fixed number of TCIstates for the subset of TCI states based on the ascending or descendingorder.
 24. The apparatus of claim 19, wherein the means for selectivelytriggering the beam failure reporting procedure further comprises: meansfor triggering the beam failure reporting procedure when all beams ofthe beam failure detection set have a block error rate (BLER) greaterthan an out-of-sync (OOS) BLER.
 25. A non-transitory computer-readablemedium storing code for wireless communication at a user equipment (UE),the code comprising instructions executable by a processor to: receive aconfiguration message indicating a set of transmission configurationindicator (TCI) states for downlink data transmissions to the UE;identify one or more reference signals to monitor for beam failuredetection based at least in part on the indicated set of TCI states;identify one or more beam failure detection beams based at least in parton the indicated set of TCI states and the identified one or morereference signals; monitor the identified one or more reference signalsusing the identified one or more beam failure detection beams; andselectively trigger a beam failure reporting procedure based at least inpart on the monitoring.
 26. The non-transitory computer-readable mediumof claim 25, wherein the code comprising instructions executable by theprocessor to identify the one or more reference signals to monitor forbeam failure detection further comprises instructions executable by theprocessor to: determine a reference signal type associated with each TCIstate in the set of TCI states; and select, from the set of TCI states,a subset of TCI states for beam failure detection based at least in parton the reference signal type associated with each TCI state in the setof TCI states.
 27. The non-transitory computer-readable medium of claim26, wherein the code comprising instructions executable by the processorto determine the reference signal type associated with each TCI state inthe set of TCI states further comprises instructions executable by theprocessor to: determine that a TCI state in the set of TCI states isassociated with multiple reference signal types; and select, based atleast in part on an entry associated with the TCI state, one of thereference signal types associated with the TCI state for use inselecting the subset of TCI states.
 28. The non-transitorycomputer-readable medium of claim 27, wherein the entry associated withthe TCI state is a Type D entry of the TCI state.
 29. The non-transitorycomputer-readable medium of claim 26, wherein the code comprisinginstructions executable by the processor to select the subset of TCIstates for beam failure detection comprises instructions executable bythe processor to: determine an ascending or descending order of TCIstates in the set of TCI states; and identify a fixed number of TCIstates for the subset of TCI states based on the ascending or descendingorder.
 30. The non-transitory computer-readable medium of claim 25,wherein the code comprising instructions executable by the processor toselectively trigger the beam failure reporting procedure furthercomprises instructions executable by the processor to: trigger the beamfailure reporting procedure when all beams of the beam failure detectionset have a block error rate (BLER) greater than an out-of-sync (OOS)BLER.